Electrode for gaseous tubes



March 1941- M. FLETCHER I 2,233,476 I ELECTRODE FOR GASEOUS TUBES FiledAug. 24, 1939 INVENTOR Milton Fletcher ATTORNEY Patented Mar. 4, 1941UNITED STATES PATENT OFFICE ELECTRODE FOR GASEOUS TUBES Milton Fletcher,New York, N. Y.

Application August 24, 1939, Serial No. $1,682

' Claims. (cl. 176-126) This invention relates to new and usefulimprovements in an electrode for gaseous tubes.

Heretofore it has been customary to construct the electrodes in vacuumtubes of solid or hol- '5 low cylindrical forms in order to providesufliand so reducing their life. This sputtering is known to occurduring the manufacture of the vacuum tube as well as during its use,especially when an excess local potential gradient develops,

. on or in the vicinity of the electrodes.

Numerous attempts have been made to so construct the electrodes, or thematerial of the tube surrounding it. to eliminate or reduce thissputterin g. Such attempts have met with little success.

This invention particularly proposes a novel construction of theelectrode so as to reduce, and very often completely eliminate thesputtering complained of. Particularly the invention proposes the use ofwire coiled into hollow cylin- 3'0 drlcal or hollow conical form, orother forms, to

form the main body of the electrode. It is proposed that the turns ofthese coils be closely wound. when the electrode is thus made it will befound that the ends are round due to the cur- 35 vature of the wire, andmoreover the side walls of the electrodes are formed with small roundedridges, or areas, which comprise the round shape of the wire forming thecoil. It has been found that the electrode so constructed will have arela-' tively lower flux density and a lower distribution of thedielectric flux which avoids disruption of' the metal forming theelectrode and so avoids sputtering.

Still further the invention proposes a novel means for supporting thenew electrode in a vacuum tube.

' Still further the invention proposes'the construction of an electrodeas mentioned which is 50 simple and durable and which may bemanufactured and sold at a reasonable cost.

' For further comprehension of the invention, and of the objects aridadvantages thereof, reference will be had to the following description55 and'acccmpanying drawing, and to the appended claims in which thevarious novel features of the invention are more particularl set forth.Fig. l isa fragmentary elevational view of a portion of a vacuum tubewith an electrode constructed in accordance with this invention. 5

of an electrode constructed in accordance with a still further.modification of this invention.

Fig. 7 is a horizontal sectional view taken on the line I -I of Fig. 6.20

The electrode for gaseous tubes in accordance with this inventionincludes a wire coil ill for engagement within a gaseous tube II, andprovided with a terminal wire it attached to its rear end, and extendingfrom the tube II. The

coil III is formed from a length of rounded wire which is closely wound.The bottom portion ill of the coil, and at its rear end, has its coilstapering forming a tapered rear end portion III". This rear end portionterminates in the wire end HP which iscoaxial with the coil.

The terminal I2 comprises a length of wire which is bent at its centerl2 and which is mounted on one of the turns of the rear end III of thecoil. This wire I2 is formed with several turns I2 constructed bytwisting an area thereof, immediately adjacent the bent end Il Theterminal may be engaged upon the turns of the rear end HI by engagingthe bent end I! over the free end |0 and then moving the bent end 40 i2-around and around to move it along the turns of the wire forming therear end Ill".

The electrode may be engaged into the end H of the tube II and may besupported by the terminal wire l2, and then the tube Il may be '45sealed in the regular way. A sheet of insulating material 14 of suchdielectric strength and high permittivity is rolled into a hollowcylindrical form and is disposed within the end .of the tube H, andencases the electrode Ill. This insulation material I 4 assists inlowering the maximum potential gradient occurring between the electrodeand the wall of the tube and so assist in preventing the disruption andsputtering previously explained.

20 and an inner coil 2!.

In Figs. 4 and 5 a modified form of the invention has been disclosedwhich distinguishes from the prior form in the way in which the terminalI2 is mounted in'position. According to this form of the invention theterminal I2 has a loop end l2 which is engaged transversely across asolid conical member l5 mounted within the conical rear end Ill of theelectrode. This conical member l5 has longitudinally extending groovesl6 along the diametrically opposite sides. The side portions of the loopl2" extended through these grooves. The side portions of the loop l2continue downwards and out from the open rear end of the electrode. andextend past the sides of the end F of the wire which forms theelectrode. The terminal l2 has a twisted area l2 immediately adjacentthe end In for assisting in holding the terminal in position.

In Figs. 6 and 7 another form of the invention has been disclosed whichdistinguishes from the prior form in the fact that the electrode is madefrom two coils of wire, one set into the other. Specifically theelectrode comprises an outer coil The outer coil 20 has its rear end 20formed into frusto-conical form. The inner coil has its rear end ill insimilar form. A wire terminal 22 has a central loop portion 22 engagingover one of the turns of the inner coil 2|. downwards out throughtheopening of the coil 20, and engages against the tail end 2|! formed bybending the free rear end of the coil 20 centrally.

The terminal wire 22 also has a twisted portion 22' arrangedimmediately. adjacent the end 20 so that the parts are somewhat rigidlyconnected. The cells 20' and 2| contact each other. The flux density atthe front end of the coil will be distributed to the ends of both of thecoils, and will distribute and reduce the dielectric flux and thus avoiddisruption of the metal forming the coils.

It is proposed that the electrode be made from stainless steel wire suchas nichrome wire which is especially good for high intensity andfluorescent tubing, but may also be made of nickel. chromium, or Monelmetal, or other wire found suitable for this purpose.

While I have illustrated and described the preferred embodiments of myinvention, it is to be understood that I do not limit myself to theprecise constructions herein disclosed and the right is reserved to allchanges and modifications coming within the scope of the invention asdefined in the appended claims. a

Having thus described my invention, what I claim as new, and desire tosecure by United States Letters Patent is:

1. An electrode for gaseous tubes. comprising a 2 wire coil forengagement with a gaseous tube having its rear turns progressivelyreduced in diameter to present a frusto-conical shape, said wire coilhaving the rear end of the wire from.

lar end of said coil wire disposed from said coil.

2. An electrode for gaseous tubes, comprising This loop portion 22extends a .wire coil for engagement with a gaseous tube having its rearturns progressively reduced in diameter to present a frusto-conicalshape, said wire coil having the rear end of the wire from which it wasformed extended from the rear end of said coil and bent at right anglesto the axis of said coil, and a U-shaped terminal wire having thejunction of its arms disposed within the frusto-conical portion of saidcoil, said terminal wire having its arms extended from the rear end ofsaid coiland along opposite sides of the right angular end of said coilwire and twisted about each other adjacent the face of said rightangular end of said coil wire disposed from said coil, and a conicalshaped member set into the frustoconical shaped rear end of said coil,-said terminal wire having the junction of its arms engaged oversaidconical shaped member.

3. An electrode for gaseous tubes, comprising a wire coil for engagementwith a gaseous tube having its rear turns progressively reduced indiameter to present a 'frusto-conical shape, said wire coil having therear end of the wire from which it was formed extended from the rear endof said coil and bent at right angles to the axis of said coil,'and aU-shaped terminal wire having the junction of its arms disposed withinthe frusto-conical portion of said coil, said terminal wire having itsarms extended from the rear end of said coil and along opposite sidesofthe'right angular end of said coil wire and twisted about each otheradjacent the face of said right angular end of said coil wire disposedfrom said coil; and a conical shaped member set into the frusto conicalshaped rear end of said coil, said terminal wire having the junction ofits arms engaged over said conical shaped member, said conical shapedmember being formed with longitudinal grooves on diametrically oppositesides thereof forming passages between the adjacent faces of saidconical member and said coil through diameter to present afrusto-conical shape, said' wire coil having the rear end of the wirefrom which it was formed extended from the rear end of said, coil andbent at right angles to the axis of said coil, and a U-shaped terminalwire having the junction of its arms disposed within the frusto-conicalportion of said coil, said terminal wire having its arms extended fromthe rear end of said coil and along opposite sides of the right angularend of said coil wire and twisted about each other adjacent the face ofsaid right angular end of said coil wire disposed from saidfcoil, saidcoil, comprising an outer coil and a complementary inner coil disposedwithin said outer coil, said right-angular end portion beingextendedfrom the rearmost turnof said outer coil.

5. An electrode for gaseous tubes, comprising a wire coil for engagementwith a gaseous tube having its rear turns progressively reduced indiameter to present a frusto-conical shape,- sald wire coil having therear end of the wire from.

which it was formed extended from the rear end of said coil and bent atright angles to the axis of said coil, and a U-shaped terminal wirehaving the junction of. its arms disposed withinthe frusto-conicalportion of said coil, said terminal wire having its arms extended fromthe rear end of said coil and along opposite sides of the right angularend of said coil wire and twisted about each other adjacent the face ofsaid right angular end of said coil wire disposed from said coil, saidcoil, comprising an outer coil and a complementary inner 'coll disposedwithin said outer coil, said right-angular end rtion being extended fromthe reannost turn of said outer coil, said terminal wire having thejunction of its arms looped over a. turn of the frustoconical portion ofsaid inner coil to'cooperate with the turned portion of the arms of saidter minal wire in locking said coils together.

MILTON FLETCHER.

